Thanks for the quick reply! I have seen that infograph on the Stonemaier website, but it doesn't list Tuscany EE in any of the main columns as a way to "have everything." Tuscany EE is listed in its own separate little box, so it's unclear whether or not the upgrade kit is necessary if you own Tuscany EE.
Tuscany EE has three additions to the game:
1) The extended board with four seasons/wooden star map
2) Special workers
3) Structure cards
If you are looking to add Mamas/Papas, New/Advanced Visitors, etc.. you will not find them in Tuscany EE.